The mechanism of magnetic field radioprotection is based on the principle of nuclear and electron spin conservation. Spin is an intrinsic quantum mechanical property of the electron and can be characterized as being either “up” or “down”. All chemical reactions are spin selective and allow only for those spin states of reactants in which the total spin is identical to that of products. Therefore, if one can control the spin states, one can control the chemical reaction. This is important since it allows for a magnetic interaction that can be used as a mechanism for control of that reaction. Control is achieved using an external magnetic field produced by either permanent magnets or electromagnetic coils. The magnetic field causes spin conversion that switches the reaction from a spin forbidden to a spin-allowed state. Not all reactions can be controlled in this manner but those that show this magnetic field effect (MFE) (e.g., Buchachenko A L, MIE versus CIE: Comparative Analysis of Magnetic and Classical Isotope Effects, Chem. Rev. 95, 2507-2528 (1995), and Buchachenko A L, Magnetic Isotope Effect: Nuclear Spin Control of Chemical Reactions, Phys. Chem. 105, 44, (2001)) have spin-selective processes, such as the radical pair mechanism (RPM). For radical pairs (RP), the magnetic field increases the probability of allowed spin states and thus an enhancement of radical pair recombination. (See, e.g., Grissom, C. B., Magnetic Field Effects in Biology: A Survey of Possible Mechanisms with Emphasis on Radical-Pair Recombination, Chem. Rev., 95(1), 3-24 (1995).)
In radiotherapy, radiolysis of water molecules produces highly reactive radicals—including hydrogen radical (H.), and a hydroxyl radical (OH.). An additional radical is formed when the hydrogen radical interacts with molecular oxygen to form highly reactive hydroperoxyl radical (HO2′). The inventors propose that the magnetic field effect will reduce the damaging effects of the radicals and the subsequent cell damage. There is little rigorous research on this topic and some of the literature seems contradictory on whether a low static magnetic field is positive, negative or has no biological effect. What is clear is that no researcher has done a systematic study of the biological effect of low static fields during radiolysis. For example, Rockwell reported in an article entitled Influence of a 1400-gauss Magnetic Field on the Radiosensitivity and Recovery of EMT6 Cells in Vitro, Department of Therapeutic Radiology, Yale University, School of Medicine, 333 Cedar Street, New Haven, Conn., 06510, U.S.A, 1977, Vol. 31, No. 2, Pages 153-160, that there was no effect on radiosensitivity using a low static magnetic field during radiation exposure. However, only a single field strength of 1400 G was used. The present inventors' research shows that that such a field would have been too large to see an effect. In supporting literature, Sarvestani, et al. reported in an article entitled Static Magnetic Fields Inhibit Radiation-induced in Bone Marrow Stem Cells, Department of Biophysics, Faculty of Bioscience, Tarbiat Modares University, Tehran, Iran, a 20% improvement in survival of bone marrow stem cells when exposed to 0.5 Gy radiation and 5-30 G magnetic field. Alikamanoğlu et al. reported in an article entitled Effect of Magnetic field and Gamma radiation on Paulowinia Tomentosa Tissue Culture, Plant Cell Tissue and Organ Culture, 83(1): 109-114, on the regenerative effects of a low magnetic field to plant cells when exposed to 10-25 Gy gamma radiation. Also, U.S. Pat. No. 6,926,659 describes the combination of applying a magnetic field during irradiation but claims that the combination of the two methods enhances cell death, which is precisely the opposite of the results obtained by the inventors and described below.
Thus, the prior art provides contradictory evidence regarding whether there is an effect when a magnetic field is applied to irradiated cells.